Excellent video, thank you for that! Now a question for anybody that has watched it, is it just me or are they chanting Namo Shivaya as the mantra for the "Lord of the Dance"? Is it Nataraja (Shiva) that they're singing praises to?

"My religion is not deceiving myself."Jetsun Milarepa 1052-1135 CE

"Butchers, prostitutes, those guilty of the five most heinous crimes, outcasts, the underprivileged: all are utterly the substance of existence and nothing other than total bliss."The Supreme Source - The Kunjed Gyalpo
The Fundamental Tantra of Dzogchen Semde

And at the beginning at the 1'46" mark where the monk is chanting the mantra by himself.

"My religion is not deceiving myself."Jetsun Milarepa 1052-1135 CE

"Butchers, prostitutes, those guilty of the five most heinous crimes, outcasts, the underprivileged: all are utterly the substance of existence and nothing other than total bliss."The Supreme Source - The Kunjed Gyalpo
The Fundamental Tantra of Dzogchen Semde

A real gem of a video. But I cannot hear anything that could be the mantra of Shiva. On the other hand, the mantra at the end might be: Om namo(nama) Chenresig. I am not sure, but the ritual could be a Red Avalokiteshvara/Chenresig ritual. And it seems Dorje Drolo and the Phurba plays an important part in the ritual.
But there are people on this forum who know more about these things than I do, so further comments would be interesting.